In the digital age, organizations increasingly rely on digitally-stored data. To protect against data loss, an organization may use a backup system to back up important data. However, backing up data may consume network resources, potentially degrading the performance of a local area network.
In order to offload backup data transmission from a local area network, some backup systems may transmit backup data over a storage area network. For example, a volume of data to be backed up may be stored on a storage system connected to a storage area network. A backup system may also be connected to the storage area network. The backup system may accordingly retrieve data from the storage system.
However, in this configuration the backup system may read only raw data from the storage device (i.e., without file-system-level data). For example, the backup system may be responsible for backing up multiple heterogeneous clients (i.e., using different storage stack elements) and may be unable to read data from the various clients at the file system level. Therefore, in order to perform file-level backup operations, the host system of the volume may need to send metadata to the backup system across the local area network. For example, the host system may send extent data to help the backup system to map files to blocks of data on the storage device.
Unfortunately, if the volume of data is a striped volume (e.g., striped across multiple storage devices in the storage system), the extent data may include a very large number of extents. For example, extent data for a file of 22 GB on a striped volume where the stripe size is 64 KB may include 360448 extents. Reading each extent sequentially may consume a large amount of time, slowing the backup process considerably. In some cases, the severity of this slowing may even prevent a backup from completing within a designated backup window.